Current modeling of the tear film acknowledges the larger presence and role of mucin in its structure and function. The goal of this application is to characterize an isolated form of natural mucin far superior in purity to commercially available sources of mucin, and formulate it into ophthalmic solution vehicles. The long-term objective is to produce an artificial tear solution with the appropriate viscoelastic properties of the mucin component of the tear film to supplement the structure, stability and lubrication of the tear film. Such treatment would provide increased comfort and allow ocular surface healing in a multitude of patients with various levels and causes of dryness symptoms. The specific aims of Phase I of the proposed research are to: 1. Purify and characterize mucins from sweet dairy whey. Characterization will include analysis of amino acid sequence and carbohydrate content. 2. Assess the chemical compatibility of the mucin with standard components utilized in ophthalmic solution formulations. These components include: Buffers, Salts, Viscosifiers, Surfactants and Humectants. 3. Prepare a prototype mucin-based ophthalmic solution and characterize with respect to accepted ranges of viscosity, osmolality, pH and surface tension. PROPOSED COMMERCIAL APPLICATION The approximately 100 million dollars dry eye product market is expected to grow with the aging population and increased use of contact lenses and computer use. Severity of signs and symptoms vary significantly, and our product would be an improvement over current commercial products in virtually all cases of dry eye. Availability alone of such an innovative product would grow the market, since current products do not have a significant effect in many patients.